The aim of this study is to compare two different IVF-stimulation protocols in patients affected by PCOS: the use of a Gonadotropin-releasing hormone (GnRH) - antagonist starting on day 1 of controlled ovarian hyperstimulation (COH) versus a standard long agonist protocol; in order to assess whether it affects the number and quality of Metaphase II (MII) oocytes while reducing the risk of hyperstimulation. Since PCOS patients are also likely to be insulin resistant we also aim to evaluate how metformin affects tha IVF stimulation outcome.

Hejinen et al (1) recently conducted a meta-analysis to compare outcomes of conventional IVF in women presenting with polycystic ovary syndrome (PCOS) and non-PCOS patients. They compared nine RCTs reporting data on 458 PCOS patients (793 cycles) and 694 matched controls (1116 cycles) and concluded that in PCOS there is an increased cancellation rate, but more oocytes retrieved per pick-up and a lower fertilization rate. Overall, PCOS and control patients achieved similar pregnancy and live birth rates per cycle. The incidence of ovarian hyperstimulation syndrome (OHSS) after oocyte retrieval was rarely reported.

Our results are in accordance with this meta-analysis. Therefore, if the pregnancy and abortion rates in PCOS and controls do not differ, the main problem when dealing with PCOS in IVF is OHSS. This condition can be approached by using an antagonist instead of an agonist, by changing the kind of ovulation trigger and by co-treating patients with metformin.

• One of the currently debatable issues regarding the use of GnRH antagonists refers to the timing of GnRH antagonist initiation. A fixed protocol starting antagonist arbitrarily on Day 6 of stimulation has been used in all introductory comparative trials employing a daily antagonist administration (2). Following these trials, a flexible antagonist initiation by a follicle of 14-15 mm has been evaluated. Currently, initiation of antagonist in the early follicular phase in PCOS patients has been performed by Lainas and coll. (3) who treated patients with PCOS either with a long GnRH agonist scheme or a fixed day-1 GnRH antagonist protocol and concluded that initiation of GnRH antagonist concomitantly with recombinant FSH on day 1 is associated with an earlier follicular growth and a different hormonal environment during the follicular phase when compared with the long agonist protocol. This may lead to a reduction in the incidence of OHSS.
• Over the past 15 years, it has become increasingly recognized that insulin resistance is central to the pathogenesis of the PCOS (4). Metformin, a biguanide insulin-lowering agent, has been extensively investigated in the management of PCOS. Two recent systematic reviews (5, 6) demonstrated that metformin improves reproductive function of some women with PCOS. Metformin also appeared to improve the outcomes of ovulation induction therapies when combined with clomiphene and gonadotrophin. Tang et al. recently studied PCOS overweight patients undergoing IVF to whom they administered 850 mg bid or placebo 28 days prior to the stimulation (7). They concluded that short-term co-treatment with metformin for patients with PCOS undergoing IVF/ICSI cycles does not improve the response to stimulation but significantly improves the pregnancy outcome and reduces the risk of OHSS.

The aim of this study is to verify if using an antagonist the number and quality of MII oocytes is equal compared to a standard long agonist protocol while reducing the risk of hyperstimulation.

Outcome measures:

Primary endpoints:

• Oocytes MII Secondary endpoints
• Fertilization rates
• Pregnancy rates
• Miscarriage rates
• Incidence of OHSS

Inclusion Criteria:

• PCOS patients according to the Rotterdam consensus criteria
• Presence of both ovaries
• Absence of endometriomas detected at ultrasound
• FSH < 10 IU/L on day 3 of the cycle
• E2 < 80 pg/mL, and Pg < 1.6 ng/mL at initiation of stimulation

Exclusion Criteria:

• Congenital adrenal hyperplasia
• Cushing's syndrome
• Androgen-producing tumours
• Hyperprolactinaemia and thyroid dysfunction
• Age > 38 years
• Serum FSH levels > 10 mIU/ml